Market adoption of wireless LAN (WLAN) technology has exploded, as users from a wide range of background and vertical industries have brought this technology into their homes, offices, and increasingly into the public air space. This inflection point has highlighted not only the limitations of earlier-generation systems, but also the changing role that WLAN technology now plays in people's work and lifestyles across the globe. Indeed, WLANs are rapidly changing from convenience networks to business-critical networks. Increasingly users are depending on WLANs to improve the timeliness and productivity of their communications and applications, and in doing so, require greater visibility, security, management, and performance from their network.
Voice codecs usually operate with a loss rate up to 10-15 percent, which in wireless networks may only be guaranteed with a very good signal (e.g., −65 dbm) and low interference. Such conditions are typically not met in wireless mesh network, where the error rate may be as high as 25%, which is why some claim that many wireless mesh networks do not adequately support voice sessions. A problem is that codecs are tuned for relatively reliable networks (e.g., wired networks) and are optimized for small packets as opposed to redundancy and latency. In particular, codecs may have difficulties adapting to sequential multiple packet loss. On the other hand, a radio network is not as reliable as wired networks. In addition, wireless mesh networking has a multiplying effect since it relies on multiple radio hops using multiple radio technologies.
A radio mesh network can be tuned to retry packets many times at each hop. However, a retry has a good chance of meeting the same interference as the original packet for some amount of time. Also, each retry costs as much as sending a new packet over a given hop, causing congestion at portions of the mesh network that operate at the same frequency. As a result, those retries add latency to both the original packet and all other packets in the mesh network, and degrade the mesh network capacity at the expense of other voice sessions.